The present invention relates to devices for the collection and injection of small volumes of fluid into an animal or human subject, or even inanimate objects, and more particularly, concerns a microsyringe useful for such purpose without the need for pistons, plungers or the like within the syringe.
There are many instances when small amounts of fluid have to be injected into or collected from a patient. For instance, some medications which are prescribed for a patient are in the microliter volume range. Use of standard hospital and medical type syringes for such a small volume range has proven impractical inasmuch as many of these syringes handle volumes in the milliliter volume range. However, microliter volume syringes have been fabricated and utilized for these small range applications. Generally speaking, these microliter volume syringes have been fabricated along the lines of the bigger syringes, i.e., they rely upon the incorporation of a slidable piston or plunger inside the barrel of the syringe. In such a small assembly, this piston must be matched inside the barrel with close accuracy in order for such a small syringe to be functional. This leads to a significantly high expense of manufacture. In addition, handling such a small syringe has been inconvenient, especially due to its fragility since most syringes of this small type are made of glass. The pistons in these syringes are also very thin and are easily damaged. Accordingly, with the deficiencies that are inherent, in the presently known and used small dose syringes, particularly in the microliter volume range, an improved microsyringe for small volume ranges is still being sought. Such an improvement to overcome the aforementioned deficiencies is the basis upon which the present invention is directed.